1. The Nitrogen Cycle C. Doka A. Greenberg K. Guymon Z. Reidy

2. Nitrogen Fixation 90% of fixation is done by bacteria -Cyanobacteria converts the nitrogen into ammonia and ammonium N 2 + 3N 2 -> 2NH 3

3. Nitrification If the ammonia is not used directly by the plant, aerobic bacteria can use oxygen to convert nitrogen to nitrite and further to nitrate 2NH 3 + 3O 2 - > 2NO 2 + 2H+ + 2H 2 O 2 NO 2 - + O 2 -> 2NO 3 -

4. Ammonification Dead plants and animals leave nitrogen which bacteria converts the nutrients back to ammonium and ammonia. Then the anaerobic bacteria can convert it to nitrogen gas through the process of denitrification. NO3- + CH2O + H+ -> ½ N2O + CO2 + 1½ H2O

5. The atmosphere is the biggest reservoir of nitrogen When plants are not able to nitrogen fixation they use assimilation to absorb the ammonium and nitrate We as humans do not directly consume nitrogen. We have to consume plants or other plant consuming animals